/* $FreeBSD: releng/11.2/sys/dev/usb/usb_parse.c 331722 2018-03-29 02:50:57Z eadler $ */
/*-
 * Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifdef USB_GLOBAL_INCLUDE_FILE
#include USB_GLOBAL_INCLUDE_FILE
#endif

/*------------------------------------------------------------------------*
 *    usb_desc_foreach
 *
 * This function is the safe way to iterate across the USB config
 * descriptor. It contains several checks against invalid
 * descriptors. If the "desc" argument passed to this function is
 * "NULL" the first descriptor, if any, will be returned.
 *
 * Return values:
 *   NULL: End of descriptors
 *   Else: Next descriptor after "desc"
 *------------------------------------------------------------------------*/
struct usb_descriptor *
usb_desc_foreach(struct usb_config_descriptor *cd,
    struct usb_descriptor *_desc)
{
    uint8_t *desc_next;
    uint8_t *start;
    uint8_t *end;
    uint8_t *desc;

    /* be NULL safe */
    if (cd == NULL)
        return (NULL);

    /* We assume that the "wTotalLength" has been checked. */
    start = (uint8_t *)cd;
    end = start + UGETW(cd->wTotalLength);
    desc = (uint8_t *)_desc;

    /* Get start of next USB descriptor. */
    if (desc == NULL)
        desc = start;
    else
        desc = desc + desc[0];

    /* Check that the next USB descriptor is within the range. */
    if ((desc < start) || (desc >= end))
        return (NULL);        /* out of range, or EOD */

    /* Check that the second next USB descriptor is within range. */
    desc_next = desc + desc[0];
    if ((desc_next < start) || (desc_next > end))
        return (NULL);        /* out of range */

    /* Check minimum descriptor length. */
    if (desc[0] < 3)
        return (NULL);        /* too short descriptor */

    /* Return start of next descriptor. */
    return ((struct usb_descriptor *)desc);
}

/*------------------------------------------------------------------------*
 *    usb_idesc_foreach
 *
 * This function will iterate the interface descriptors in the config
 * descriptor. The parse state structure should be zeroed before
 * calling this function the first time.
 *
 * Return values:
 *   NULL: End of descriptors
 *   Else: A valid interface descriptor
 *------------------------------------------------------------------------*/
struct usb_interface_descriptor *
usb_idesc_foreach(struct usb_config_descriptor *cd,
    struct usb_idesc_parse_state *ps)
{
    struct usb_interface_descriptor *id;
    uint8_t new_iface;

    /* retrieve current descriptor */
    id = (struct usb_interface_descriptor *)ps->desc;
    /* default is to start a new interface */
    new_iface = 1;

    while (1) {
        id = (struct usb_interface_descriptor *)
            usb_desc_foreach(cd, (struct usb_descriptor *)id);
        if (id == NULL)
            break;
        if ((id->bDescriptorType == UDESC_INTERFACE) &&
            (id->bLength >= sizeof(*id))) {
            if (ps->iface_no_last == id->bInterfaceNumber)
                new_iface = 0;
            ps->iface_no_last = id->bInterfaceNumber;
            break;
        }
    }

    if (ps->desc == NULL) {
        /* first time or zero descriptors */
    } else if (new_iface) {
        /* new interface */
        ps->iface_index ++;
        ps->iface_index_alt = 0;
    } else {
        /* new alternate interface */
        ps->iface_index_alt ++;
    }
#if (USB_IFACE_MAX <= 0)
#error "USB_IFACE_MAX must be defined greater than zero"
#endif
    /* check for too many interfaces */
    if (ps->iface_index >= USB_IFACE_MAX) {
        DPRINTF("Interface limit reached\n");
        id = NULL;
    }

    /* store and return current descriptor */
    ps->desc = (struct usb_descriptor *)id;
    return (id);
}

/*------------------------------------------------------------------------*
 *    usb_edesc_foreach
 *
 * This function will iterate all the endpoint descriptors within an
 * interface descriptor. Starting value for the "ped" argument should
 * be a valid interface descriptor.
 *
 * Return values:
 *   NULL: End of descriptors
 *   Else: A valid endpoint descriptor
 *------------------------------------------------------------------------*/
struct usb_endpoint_descriptor *
usb_edesc_foreach(struct usb_config_descriptor *cd,
    struct usb_endpoint_descriptor *ped)
{
    struct usb_descriptor *desc;

    desc = ((struct usb_descriptor *)ped);

    while ((desc = usb_desc_foreach(cd, desc))) {
        if (desc->bDescriptorType == UDESC_INTERFACE) {
            break;
        }
        if (desc->bDescriptorType == UDESC_ENDPOINT) {
            if (desc->bLength < sizeof(*ped)) {
                /* endpoint descriptor is invalid */
                break;
            }
            return ((struct usb_endpoint_descriptor *)desc);
        }
    }
    return (NULL);
}

/*------------------------------------------------------------------------*
 *    usb_ed_comp_foreach
 *
 * This function will iterate all the endpoint companion descriptors
 * within an endpoint descriptor in an interface descriptor. Starting
 * value for the "ped" argument should be a valid endpoint companion
 * descriptor.
 *
 * Return values:
 *   NULL: End of descriptors
 *   Else: A valid endpoint companion descriptor
 *------------------------------------------------------------------------*/
struct usb_endpoint_ss_comp_descriptor *
usb_ed_comp_foreach(struct usb_config_descriptor *cd,
    struct usb_endpoint_ss_comp_descriptor *ped)
{
    struct usb_descriptor *desc;

    desc = ((struct usb_descriptor *)ped);

    while ((desc = usb_desc_foreach(cd, desc))) {
        if (desc->bDescriptorType == UDESC_INTERFACE)
            break;
        if (desc->bDescriptorType == UDESC_ENDPOINT)
            break;
        if (desc->bDescriptorType == UDESC_ENDPOINT_SS_COMP) {
            if (desc->bLength < sizeof(*ped)) {
                /* endpoint companion descriptor is invalid */
                break;
            }
            return ((struct usb_endpoint_ss_comp_descriptor *)desc);
        }
    }
    return (NULL);
}

/*------------------------------------------------------------------------*
 *    usbd_get_no_descriptors
 *
 * This function will count the total number of descriptors in the
 * configuration descriptor of type "type".
 *------------------------------------------------------------------------*/
uint8_t
usbd_get_no_descriptors(struct usb_config_descriptor *cd, uint8_t type)
{
    struct usb_descriptor *desc = NULL;
    uint8_t count = 0;

    while ((desc = usb_desc_foreach(cd, desc))) {
        if (desc->bDescriptorType == type) {
            count++;
            if (count == 0xFF)
                break;            /* crazy */
        }
    }
    return (count);
}

/*------------------------------------------------------------------------*
 *    usbd_get_no_alts
 *
 * Return value:
 *   Number of alternate settings for the given interface descriptor
 *   pointer. If the USB descriptor is corrupt, the returned value can
 *   be greater than the actual number of alternate settings.
 *------------------------------------------------------------------------*/
uint8_t
usbd_get_no_alts(struct usb_config_descriptor *cd,
    struct usb_interface_descriptor *id)
{
    struct usb_descriptor *desc;
    uint8_t n;
    uint8_t ifaceno;

    /* Reset interface count */

    n = 0;

    /* Get the interface number */

    ifaceno = id->bInterfaceNumber;

    /* Iterate all the USB descriptors */

    desc = NULL;
    while ((desc = usb_desc_foreach(cd, desc))) {
        if ((desc->bDescriptorType == UDESC_INTERFACE) &&
            (desc->bLength >= sizeof(*id))) {
            id = (struct usb_interface_descriptor *)desc;
            if (id->bInterfaceNumber == ifaceno) {
                n++;
                if (n == 0xFF)
                    break;        /* crazy */
            }
        }
    }
    return (n);
}
